Weights have been incorporated into golf clubs to distribute discretionary mass in order to alter the mass characteristics. For example, weights may be incorporated to provide adjustability in characteristics such as swing weight, location of the center of gravity and manipulation of the moment of inertia of a particular golf club head. Various weight designs have been utilized that allow the manufacturer and/or consumer to alter the mass properties of a golf club head.
One example of a weight incorporated into a club head is described in U.S. Pat. No. 1,167,106 to Palmer for a Golf Club. Palmer describes a golf club that includes a threaded opening that receives threaded weight plugs for varying the weight of a cast metal golf club head. The threaded opening extends through a rear wall of the golf club head and receives a threaded plug which may be just long enough to fill the opening or it may extend further into the golf club head to increase the weight. The threaded opening is tapered so that the plug may be tightened to a desired depth. A disadvantage of the threaded weight plug is that it is constructed as a single piece. As a result, torque applied to the weight plug during use of the golf club is transmitted to the threaded portion and may result in the weight plug becoming disengaged, especially with repeated use.
In another example, described in U.S. Pat. No. 1,167,387 to Daniel, a weight socket is attached to a golf club head and to the end of a golf club shaft. Weights are installed into the socket and a screw on cap is installed on the end of the socket to secure the weights inside.
In another example, described in U.S. Pat. No. 3,075,768, a compartment is incorporated into a proximal end of the golf club adjacent a grip. The compartment holds weighting means so that the balance of the golf club can be altered after the golf club is assembled.
In yet another example, described in U.S. Pat. No. 3,606,327, a capsule is secured to a grip end of a golf club shaft and to a golf club head. Washers having different weights are inserted into each capsule and held in place by a screw. The screw extends through the centers of the washers and is threaded into an aperture at the bottom of the capsule.
Another example of a removable weight is described in U.S. Pat. No. 6,773,360 to Willett et al. for a Golf Club Having a Removable Weight. The removable weight includes a mass element and a fastener that extends through an aperture in the mass element. A golf club head body includes an interior cavity and a recess on a wall of the body. Inside the recess, a threaded opening is provided so that the fastener may extend through the mass element disposed in the recess and into the threaded opening to fasten the mass element in the recess. Because the fastener extends through the mass element and into a threaded opening in the recess, the size of the mass element and the structure of the recess are limited. Additionally, the mass element is visible to the user when installed so less variation is available for the mass element without detrimentally affecting the aesthetics of the club head.
These weight constructions have been used to alter the static mass properties of the golf club. It is desirable to provide a system for weighting a golf club golf club and a method for incorporating that system to alter the dynamic characteristics of a golf club during a swing.